What is Depression?

The map starts with the definition of depression which is a mood disorders that affects
patient’s cognition, behaviour, and physical functioning. Depression is classified according to symptoms and course of
the disease into:

Major depressive disorder /
Major depression / Unipolar depression

Dysthymia

Postpartum Depression

Seasonal Affective Disorder
(SAD)

Depressive disorder not
otherwise specified

Mixed anxiety-depression

The main type of depression and the focus of this map is Major depressive disorder (Clinical Depression)

What causes depression?

Depression etiology

It is of unknown cause, but involves hereditary,
social, developmental, and biological factors.
It is related to changes in brain monoamine neurotransmitters:
norepinephrine (NE), serotonin (5-HT), and/or dopamine (DA).

Depression pathophysiology

Although
depression is a disorder of unknown cause, many hypotheses have tried to explain
the pathophysiology of depression. Among
the most prominent of these hypotheses are those mentioned in the following map
of (Phathophysiologic Hypotheses of Depression):

Phathophysiologic Hypotheses of Depression - Click on the image to enlarge

The first
one is “Catecholamines Hypothesis” which proposes that depression
is linked to decreased brain levels of the neurotransmitters norepinephrine
(NE), serotonin (5-HT), and/or dopamine (DA).
But it has been observed that the administration of antidepressants
causes immediate increase in the synaptic levels of monoamines (NE and 5-HT) producing
antidepressants adverse effects, while the antidepressive effects
are not observed until after few weeks of dosing. That observation is explained by the second
hypothesis which is (Receptor Sensitivity Hypothesis).

According to “Receptor Sensitivity Hypothesis,”
the decrease in NE and 5-HT results in low stimulation of the postsynaptic receptors
by these monoamines, and consequently increased postsynaptic receptors'
sensitivity and number. That is how long
term administration of antidepressants is responsible for decreasing the
sensitivity "desensitization" and the number "down-regulation"
of central β-adrenergic receptors and finally producing the antidepressant
effect.

Concerning the third hypothesis which is
called “The Permissive Hypothesis,” the control of emotional behavior results
from a balance between NE and 5-HT, i.e. the decrease in both 5-HT and NE causes
depression, while the decrease in 5-HT with an increase in NE causes mania.

This map provides
you with the basic knowledge to understand the nature of the disease. In the upcoming full map of (Depression), I
will link between “Depression pathophysiology” and:

how antidepressants work (i.e. mechanisms of
action) and

what adverse effects they produce

Diagnosis of depression

In case of suspected major depressive episode:

-exclude bipolar depression;
as major depression is a unipolar disorder.

B. The symptoms cause clinically
significant impairment in social and occupational functioning

C. The symptoms are not due to
effects of a substance (e.g., a drug of abuse, a medication),

a general medical condition (e.g.,
hypothyroidism) mood-incongruent delusions or hallucinations

D. The symptoms are not better
accounted for by bereavement (loss of a loved one)

Treatment of Depression

Nonpharmacological Treatment of Depression,
includes:

Psychotherapy could be the first-line therapy in mild to
moderate depression, but not used alone in case of acute severe and/or
psychotic major depressive disorder.

Electroconvulsive Therapy (ECT) is safe and effective for
severe mental illnesses, including all subtypes of major depression. It is reserved for treatment-resistant cases
and delusional depressions.

Light therapy.

Pharmacological Treatment of Depression

It should be understood on the basis of depression
pathophysiology. Antidepressants
mechanisms of actions and accordingly adverse effects and –if present- drug
interactions, contraindications, patient education, advantages, drug
discontinuation symptoms and precautions of the following depression
medications are stated in the map in the form of mini-maps for each
antidepressant, linking between the key information about every medication of
the following:

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Who are "Zooming out"?

We are a team of pharmacists who are interested in the science of pharmacotherapy, which is represented through this site. At this site we are trying to help whoever experiences difficulty understanding and memorizing diseases and their corresponding treatment approaches. We are convinced with the idea of connecting information together and making links between it, to prevent its escape from minds, so we are presenting diseases using the concept mapping and the mind mapping methods to help in dealing with “information explosion!” in the field of pharmacotherapy. We really hope that you find this site helpful. Know more about those who are Zooming out!